Ejection system
Injection moulds for thermoplastics - Design and production

When the mold is opened, the part is ejected from the mold by the ejection device.

The latter can be made up of ejectors, a debeater plate or a compressed-air system.

The ejection stroke must be sufficient to ensure that the part is evacuated from the mold cavity with the mold open.

Release mechanisms are located on the side of the mold where the part remains attached (often on the moving part side).

In general, shrinkage retains the parts on the cores and, if necessary, small undercuts can be used to impose this result or, on the contrary, to ensure that the part remains in the cavity.

Part adhesion depends on the coefficient of friction, the modulus of elasticity of the polymer at the moment of ejection, and shrinkage.